BUG-5280: add basic concept of ClientSnapshot

[controller.git] / opendaylight / md-sal / sal-distributed-datastore / src / main / java / org / opendaylight / controller / cluster / datastore / FrontendReadOnlyTransaction.java

diff --git a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/FrontendReadOnlyTransaction.java b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/FrontendReadOnlyTransaction.java
new file mode 100644 (file)
index 0000000..36a876b
--- /dev/null
+++ b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/FrontendReadOnlyTransaction.java
@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2016 Cisco Systems, Inc. and others.  All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.controller.cluster.datastore;
+
+import com.google.common.base.Optional;
+import com.google.common.base.Preconditions;
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.NotThreadSafe;
+import org.opendaylight.controller.cluster.access.commands.ExistsTransactionRequest;
+import org.opendaylight.controller.cluster.access.commands.ExistsTransactionSuccess;
+import org.opendaylight.controller.cluster.access.commands.ReadTransactionRequest;
+import org.opendaylight.controller.cluster.access.commands.ReadTransactionSuccess;
+import org.opendaylight.controller.cluster.access.commands.TransactionAbortRequest;
+import org.opendaylight.controller.cluster.access.commands.TransactionAbortSuccess;
+import org.opendaylight.controller.cluster.access.commands.TransactionRequest;
+import org.opendaylight.controller.cluster.access.commands.TransactionSuccess;
+import org.opendaylight.controller.cluster.access.concepts.RequestEnvelope;
+import org.opendaylight.controller.cluster.access.concepts.RequestException;
+import org.opendaylight.controller.cluster.access.concepts.UnsupportedRequestException;
+import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
+
+/**
+ * Read-only frontend transaction state as observed by the shard leader.
+ *
+ * @author Robert Varga
+ */
+@NotThreadSafe
+final class FrontendReadOnlyTransaction extends FrontendTransaction {
+    private final ReadOnlyShardDataTreeTransaction openTransaction;
+
+    private FrontendReadOnlyTransaction(final AbstractFrontendHistory history,
+            final ReadOnlyShardDataTreeTransaction transaction) {
+        super(history, transaction.getIdentifier());
+        this.openTransaction = Preconditions.checkNotNull(transaction);
+    }
+
+    static FrontendReadOnlyTransaction create(final AbstractFrontendHistory history,
+            final ReadOnlyShardDataTreeTransaction transaction) {
+        return new FrontendReadOnlyTransaction(history, transaction);
+    }
+
+    // Sequence has already been checked
+    @Override
+    @Nullable TransactionSuccess<?> handleRequest(final TransactionRequest<?> request, final RequestEnvelope envelope,
+            final long now) throws RequestException {
+        if (request instanceof ExistsTransactionRequest) {
+            return handleExistsTransaction((ExistsTransactionRequest) request);
+        } else if (request instanceof ReadTransactionRequest) {
+            return handleReadTransaction((ReadTransactionRequest) request);
+        } else if (request instanceof TransactionAbortRequest) {
+            return handleTransactionAbort((TransactionAbortRequest) request, envelope, now);
+        } else {
+            throw new UnsupportedRequestException(request);
+        }
+    }
+
+    private TransactionSuccess<?> handleTransactionAbort(final TransactionAbortRequest request,
+            final RequestEnvelope envelope, final long now) throws RequestException {
+        openTransaction.abort();
+        return new TransactionAbortSuccess(openTransaction.getIdentifier(), request.getSequence());
+    }
+
+    private ExistsTransactionSuccess handleExistsTransaction(final ExistsTransactionRequest request)
+            throws RequestException {
+        final Optional<NormalizedNode<?, ?>> data = openTransaction.getSnapshot().readNode(request.getPath());
+        return recordSuccess(request.getSequence(), new ExistsTransactionSuccess(openTransaction.getIdentifier(),
+            request.getSequence(), data.isPresent()));
+    }
+
+    private ReadTransactionSuccess handleReadTransaction(final ReadTransactionRequest request)
+            throws RequestException {
+        final Optional<NormalizedNode<?, ?>> data = openTransaction.getSnapshot().readNode(request.getPath());
+        return recordSuccess(request.getSequence(), new ReadTransactionSuccess(openTransaction.getIdentifier(),
+            request.getSequence(), data));
+    }
+}